Methods for Refracturing a Subterranean Formation

ABSTRACT

Methods for refracturing a subterranean formation via a hydrocarbon well that includes a downhole tubular extending within a wellbore formed within the subterranean formation. The methods include positioning a plurality of isolation structures within a tubular conduit defined by the downhole tubular to define a plurality of spaced-apart stimulation zones. The downhole tubular includes a plurality of spaced-apart existing perforations. The methods also include stimulating an initial region of the subterranean formation, which is associated with an initial stimulation zone of the plurality of spaced-apart stimulation zones, via an initial subset of the plurality of spaced-apart existing perforations and subsequently sealing the initial subset of the plurality of spaced-apart existing perforations. The methods further include establishing fluid communication between the initial stimulation zone and an adjacent stimulation zone and stimulating an adjacent region of the subterranean formation that is associated with the adjacent stimulation zone.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/525,041 filed Jun. 26, 2017 titled “Methods for Refracturing aSubterranean Formation,” and is related to and will claim benefit ofU.S. Provisional Application Ser. No. 62/463,389 filed Feb. 24, 2017titled “Method for Well Stimulation,” the disclosures of which areincorporated herein by reference in their entireties.

This application is related to U.S. Provisional Application Ser. No.62/525,043 filed Jun. 26, 2017 titled “Methods for Refracturing aSubterranean Formation Using Shearable Ball Seats for Zone Isolation,”the disclosure of which is incorporated herein by reference in itsentirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to methods for refracturing asubterranean formation and more specifically to methods for refracturinga subterranean formation via a hydrocarbon well that includes a downholetubular extending within a wellbore formed within the subterraneanformation.

BACKGROUND OF THE DISCLOSURE

Conventional refracturing operations generally have been performed bybullheading a stimulant fluid stream, which may include a stimulantfluid, a proppant, and/or a proppant slurry, into a wellbore while anentire lateral is open, simultaneously pumping the stimulant fluidstream through all perforations. Such conventional refracturingoperations colloquially are referred to in the industry as a “pump andpray” operation, as they provide little control over whichperforation(s) actually receive the stimulant fluid stream and/or whichregion(s) of a subterranean formation are refractured.

In a variant of these conventional refracturing operations, and afterpumping the stimulant fluid stream for a given period of time, a numberof ball sealers, chemical diverters, particulate diverters, and/or othersealing devices may be deployed within the hydrocarbon well with thegoal of sealing the perforations that are most receptive of thestimulant fluid stream. Subsequently, the stimulant fluid stream may bepumped through the remaining perforations to re-stimulate otherregion(s) of the subterranean formation. This methodology, while simpleand generally low-cost, suffers from an inability to target thestimulant fluid stream to specific region(s) of the subterraneanformation and/or to provide high stimulant fluid stream injection ratesthrough specific perforation(s).

Another conventional refracturing operation involves the use of coiledtubing, together with a straddle packer assembly, to supply thestimulant fluid stream to desired region(s) of the subterraneanformation. While more targeted than “pump and pray,” coiled tubing alsosuffers from low injection rates (due to the small diameter of thecoiled tubing and associated friction pressure losses), high costs, andoperational risks.

Yet another conventional refracturing operation involves setting a lineracross existing perforations. The liner may have a defined or expandablediameter and may be cemented or not. After the liner is set, thisconventional refracturing operation is similar to initial completion ofthe well. Such a conventional refracturing operation is operationallydifficult and very costly.

While the above-described conventional refracturing operationscollectively may provide the ability to refracture many subterraneanformations, they suffer from the above-described limitations. Thus,there exists a need for improved methods for refracturing a subterraneanformation.

SUMMARY OF THE DISCLOSURE

Methods for refracturing a subterranean formation via a hydrocarbon wellthat includes a downhole tubular extending within a wellbore formedwithin the subterranean formation. The methods include positioning aplurality of isolation structures within a tubular conduit defined bythe downhole tubular to define a plurality of spaced-apart stimulationzones within the tubular conduit. The downhole tubular includes aplurality of spaced-apart existing perforations. The plurality ofspaced-apart existing perforations provides fluid communication betweenthe tubular conduit and the subterranean formation, and each stimulationzone in the plurality of spaced-apart stimulation zones includes acorresponding subset of the plurality of spaced-apart existingperforations.

Subsequent to the positioning, the methods also include stimulating aninitial region of the subterranean formation. The initial region of thesubterranean formation is associated with an initial stimulation zone ofthe plurality of spaced-apart stimulation zones. The initial stimulationzone includes an initial subset of the plurality of spaced-apartexisting perforations, and the stimulating the initial region includesinjecting a stimulant fluid from a surface region, via the tubularconduit, through the initial subset of the plurality of spaced-apartexisting perforations, and into the subterranean formation. The methodsalso include resisting flow of the stimulant fluid through stimulationzones that are downhole from the initial stimulation zone duringinjection of the stimulant fluid through the initial subset of theplurality of spaced-apart existing perforations. The methods theninclude sealing the initial subset of the plurality of spaced-apartexisting perforations.

The methods further include establishing fluid communication between theinitial stimulation zone and an adjacent stimulation zone within thetubular conduit while maintaining the sealing of the initial subset ofthe plurality of spaced-apart existing perforations. The adjacentstimulation zone is downhole from the initial stimulation zone.

The methods also include stimulating an adjacent region of thesubterranean formation that is associated with the adjacent stimulationzone. The adjacent stimulation zone includes an adjacent subset of theplurality of spaced-apart existing perforations. The stimulating theadjacent region of the subterranean formation includes flowing thestimulant fluid from the surface region, via the tubular conduit,through the initial stimulation zone, through the adjacent subset of theplurality of spaced-apart existing perforations, and into thesubterranean formation while resisting flow of the stimulant fluidthrough stimulation zones that are downhole from the adjacentstimulation zone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic example of hydrocarbon wells that may be utilizedto perform the methods according to the present disclosure.

FIG. 2 is a flowchart depicting methods, according to the presentdisclosure, for refracturing a subterranean formation via a hydrocarbonwell.

FIG. 3 illustrates an example of a portion of the methods of FIG. 2.

FIG. 4 illustrates another example of a portion of the methods of FIG.2.

FIG. 5 illustrates another example of a portion of the methods of FIG.2.

FIG. 6 illustrates another example of a portion of the methods of FIG.2.

FIG. 7 illustrates another example of a portion of the methods of FIG.2.

FIG. 8 illustrates another example of a portion of the methods of FIG.2.

FIG. 9 illustrates another example of a portion of the methods of FIG.2.

FIG. 10 illustrates another example of a portion of the methods of FIG.2.

FIG. 11 illustrates another example of a portion of the methods of FIG.2.

FIG. 12 illustrates another example of a portion of the methods of FIG.2.

FIG. 13 illustrates another example of a portion of the methods of FIG.2.

FIG. 14 illustrates another example of a portion of the methods of FIG.2.

FIG. 15 illustrates another example of a portion of the methods of FIG.2.

FIG. 16 illustrates another example of a portion of the methods of FIG.2.

FIG. 17 illustrates another example of a portion of the methods of FIG.2.

FIG. 18 illustrates another example of a portion of the methods of FIG.2.

FIG. 19 illustrates another example of a portion of the methods of FIG.2.

FIG. 20 illustrates another example of a portion of the methods of FIG.2.

FIG. 21 illustrates another example of a portion of the methods of FIG.2.

FIG. 22 illustrates another example of a portion of the methods of FIG.2.

DETAILED DESCRIPTION AND BEST MODE OF THE DISCLOSURE

FIGS. 1-22 provide examples of methods 200, according to the presentdisclosure, of hydrocarbon wells 40 that may be utilized to performmethods 200, and/or of various steps that may be performed duringmethods 200. Elements that serve a similar, or at least substantiallysimilar, purpose are labeled with like numbers in each of FIGS. 1-22,and these elements may not be discussed in detail herein with referenceto each of FIGS. 1-22. Similarly, all elements may not be labeled ineach of FIGS. 1-22, but reference numerals associated therewith may beutilized herein for consistency. Elements, components, and/or featuresthat are discussed herein with reference to one or more of FIGS. 1-22may be included in and/or utilized with any of FIGS. 1-22 withoutdeparting from the scope of the present disclosure. In general, elementsthat are likely to be included in a particular embodiment areillustrated in solid lines, while elements that are optional areillustrated in dashed lines. However, elements that are shown in solidlines may not be essential and, in some embodiments, may be omittedwithout departing from the scope of the present disclosure.

FIG. 1 is a schematic example of hydrocarbon wells 40 that may beutilized with, or to perform, methods 200 according to the presentdisclosure, which are discussed in more detail herein with reference toFIG. 2. Hydrocarbon wells 40 include a downhole tubular 60 that definesa tubular conduit 62. Downhole tubular 60 extends within a wellbore 50that extends within a subterranean formation 30. Wellbore 50 also may bereferred to herein as extending within a subsurface region 20, asextending between a surface region 10 and subsurface region 20, and/oras extending between surface region 10 and subterranean formation 30.Examples of downhole tubular 60 include any suitable tube, casingsegment, casing string, casing, liner segment, liner string, and/orliner that may extend within wellbore 50, that may extend betweensurface region 10 and subterranean formation 30, and/or that may be hungoff, within wellbore 50, below the surface region and/or within thesubsurface region.

Wellbore 50 may define an uphole direction 52, which may point and/orextend, along the wellbore, in a direction that generally is toward anuphole end 42 of the hydrocarbon well and/or away from a downhole, ortoe, end 44 of the hydrocarbon well. Wellbore 50 also may define adownhole direction 54, which may point and/or extend, along thewellbore, in a direction that generally is away from uphole end 42and/or is toward downhole end 44. Wellbore 50 also may have and/ordefine a heel, or heel region, 43. Heel 43 may include and/or be atransition region between a vertical portion, or region, of the wellboreand a horizontal, or deviated, portion, or region, of the wellbore.

Wellbore 50 may have any suitable shape and/or trajectory withinsubsurface region 20. As examples, wellbore 50 may include one or moreof a vertical region, a deviated region, and/or a horizontal, or atleast substantially horizontal, region.

Hydrocarbon wells 40 may include a plurality of isolation structures 90,which may be positioned within tubular conduit 62. Isolation structures90 may be spaced-apart from one another along a length of the tubularconduit and/or may form, define, delineate, and/or bound a plurality ofdiscrete, distinct, and/or spaced-apart stimulation zones 110.

Downhole tubular 60 may include a plurality of spaced-apart existingperforations 70, which also may be referred to herein as a plurality ofperforations 70. Existing perforations 70 previously may have beenutilized to stimulate subterranean formation 30 and/or to produce ahydrocarbon from the subterranean formation. Existing perforations 70may be formed and/or may be present within downhole tubular 60 prior toperforming, or prior to initiation of, methods 200 that are disclosedherein. Each stimulation zone 110 may include a corresponding subset ofthe plurality of spaced-apart existing perforations. As examples, aninitial stimulation zone 112 may include an initial subset 72 of theplurality of spaced-apart existing perforations, an adjacent stimulationzone 114 may include an adjacent subset 74 of the plurality ofspaced-apart existing perforations, and/or a subsequent stimulation zone116 may include a subsequent subset 76 of the plurality of spaced-apartexisting perforations. A most uphole subset of existing perforations 70may extend within heel region 43, and a most downhole subset of existingperforations 70 may extend within toe region 44.

As illustrated in dashed lines in FIG. 1, downhole tubular 60 also mayinclude a plurality of spaced-apart new perforations 80. Newperforations 80 may be formed during, or as a result of, methods 200.Additionally or alternatively, new perforations 80 may be formed withinthe downhole tubular subsequent to stimulation of the subterraneanformation via existing perforations 70 and/or subsequent to productionof the hydrocarbon from the subterranean formation via the existingperforations.

Isolation structures 90 may include corresponding isolation devices 100,and an initial isolation device 102 may extend between, or delineate,initial stimulation zone 112 and adjacent stimulation zone 114. Anadjacent isolation device 104 may extend between, or delineate, adjacentstimulation zone 114 and subsequent stimulation zone 116. A subsequentisolation device 106 may extend between, or delineate, subsequentstimulation zone 116 and a remainder of tubular conduit 62 that extendsdownhole, or in downhole direction 54, from the subsequent stimulationzone.

Isolation structures 90 may include any suitable structure that mayform, define, or delineate stimulation zones 110. Additionally oralternatively, isolation structures may include any suitable structurethat may, or that may be utilized to, isolate, fluidly isolate,hydraulically isolate, and/or selectively isolate stimulation zones 110from one another, at least within tubular conduit 62.

As an example, and as illustrated in dashed lines in FIG. 1 and in moredetail in FIGS. 6, 9, 12, and 15, isolation structures 90 may includeand/or be a frangible isolation structure 92. Frangible isolationstructures 92 may be configured to selectively shatter, break apart,and/or disintegrate, such as upon receipt of, or experiencing, ashockwave, a pressure spike, and/or another suitable transition signal.Stated another way, isolation device 100 of frangible isolationstructures 92 may include and/or be a frangible or destructibleisolation device 100, such as a glass and/or ceramic isolation devicethat is configured to selectively shatter or break such as responsive toreceipt of an actuation signal or in the presence of a selectedpressure.

As another example, and as illustrated in dashed lines in FIG. 1 and inmore detail in FIGS. 7, 10, 13, and 16, isolation structures 90 mayinclude an isolation device seat 94 that is configured to receive, toselectively receive, to release, and/or to selectively release isolationdevice 100. Under these conditions, isolation device 100 also may bereferred to herein as, or may be, an isolation ball 100, and isolationdevice seat 94 also may be referred to herein as, or may be, anisolation ball seat 94.

During re-fracturing of hydrocarbon wells 40 utilizing methods 200, andas discussed in more detail herein with reference to methods 200 of FIG.2, wellbore 50 and/or tubular conduit 62 may be cleaned-out and/orcleared. The terms “cleanout” and/or “clearing” and/or “cleaning” may beused interchangeably, referring to the processes related to the removalof any obstructions and/or fill within the through bore of tubularconduit, such as, for example, frac sand, proppant, produced formationsand or other media, frac plugs, seats, perforating gun debris, ballsealers, perforation sealing devices and structures, staging material,scale, paraffin, and any other debris, etc. Subsequently, a plurality ofisolation structures 90 may be positioned within tubular conduit 62 todefine stimulation zones 110. Initial isolation device 102 may be, ormay be placed in, a closed state in which the initial isolation deviceincludes isolation structure 90 and resists fluid flow from initialstimulation zone 112 and into portions of tubular conduit 62 that aredownhole from the initial stimulation zone. Subsequently, a stimulantfluid 120 may be provided to tubular conduit 62, such as from surfaceregion 10. The stimulant fluid may flow into subterranean formation 30via initial subset 72 of existing perforations 70 and/or via an initialsubset 82 of new perforations 80, when present, to stimulate an initialregion 32 of the subterranean formation.

Subsequently, initial subset 72 of existing perforations 70 and/orinitial subset 82 of new perforations 80, when present, may be sealed,such as via and/or utilizing one or more sealing devices 130, which alsomay be referred to herein as initial sealing devices 132. This mayinclude sealing all of the initial subset of the plurality ofspaced-apart existing perforations and all of the initial subset of thenew perforations, when present. Alternatively, this may include amulti-step process that includes sealing a most fluid-receptive fractionof the initial subset of the plurality of existing perforations and/orof the initial subset of the plurality of new perforations.Subsequently, additional stimulant fluid may be injected into thesubterranean formation via one or more perforations that remain openprior to sealing all of the initial subset of the existing perforationsand all of the initial subset of the new perforations, when present.Such a process is discussed in more detail herein.

Subsequently, fluid communication may be established between initialstimulation zone 112 and adjacent stimulation zone 114, and the processmay be repeated to stimulate an adjacent region 34 of the subterraneanformation utilizing adjacent subset 74 of existing perforations 70and/or an adjacent subset 84 of new perforations 80, when present. Then,perforations present within adjacent stimulation zone 114 may be sealedwith corresponding adjacent sealing devices 134.

This process may be repeated any suitable number of times to stimulateany suitable number of regions of subterranean formation 30. As anexample, fluid communication may be established between adjacentstimulation zone 114 and subsequent stimulation zone 116, and subsequentregion 36 of the subterranean formation may be stimulated via subsequentsubset 76 of the plurality of spaced-apart existing perforations and/orvia subsequent subset 86 of the plurality of new perforations. Then,perforations present within subsequent stimulation zone 116 may besealed with corresponding subsequent sealing devices 136.

Sealing devices 130 may include and/or be any suitable structure thatmay be adapted, configured, designed, sized, and/or constructed to flowinto contact with existing perforations 70, to seal existingperforations 70, to flow into contact with new perforations 80, and/orto seal new perforations 80. Examples of sealing devices 130 includeball sealers, conformable, knotted or tentacular perforation sealingdevice (collectively hereafter referred to as “conformable sealers”),beads, poly lactic acid beads, fibers, poly lactic acid fibers, rods,and/or poly lactic acid rods.

FIG. 2 is a flowchart depicting methods 200, according to the presentdisclosure, for refracturing a subterranean formation via a hydrocarbonwell, such as one or more of hydrocarbon wells 40 of FIG. 1. FIGS. 3-22illustrate examples of portions of methods 200 of FIG. 2. Morespecifically, FIG. 3 illustrates cleaning of a tubular conduit of thehydrocarbon well, and FIG. 4 illustrates formation of new perforationswithin a downhole tubular that defines the tubular conduit. FIGS. 5, 8,11, 14, and 17 schematically illustrate methods 200, while FIGS. 6, 9,12, 15, and 18 illustrate methods 200 performed utilizing frangibleisolation structures. FIGS. 7, 10, 13, 16, and 18 illustrate methods 200performed utilizing isolation device seats configured to receivecorresponding isolation devices, and FIG. 19 illustrates a re-fracturedsubterranean formation subsequent to having methods 200 performedtherein. In addition, FIGS. 20-22 illustrate a multi-step sealingprocess that may be utilized during methods 200.

Methods 200 may include cleaning a tubular conduit at 205 and/or addingnew perforations at 210. Methods 200 include positioning a plurality ofisolation structures at 215 and may include positioning an initialisolation device at 220. Methods 200 also include stimulating an initialregion of the subterranean formation at 225, sealing an initial subsetof a plurality of perforations at 230, and/or establishing fluidcommunication between an initial stimulation zone and an adjacentstimulation zone at 235. Methods 200 further may include positioning anadjacent isolation device at 240 and include stimulating an adjacentregion of the subterranean formation at 245. Methods 200 also mayinclude sealing an adjacent subset of the plurality of perforations at250, establishing fluid communication between the adjacent stimulationzone and a subsequent stimulation zone at 255, stimulating a subsequentregion of the subterranean formation at 260, and/or clearing the tubularconduit at 265.

Cleaning the tubular conduit at 205 may include cleaning the tubularconduit in any suitable manner and may be performed prior to thepositioning at 215. As an example, the cleaning at 205 may includeflushing solids, solid matter, and/or particulate matter from thetubular conduit. As another example, the cleaning at 205 may includeremoving downhole equipment and/or devices from the tubular conduit. Asan additional example, the cleaning at 205 may be performed utilizingcoiled tubing. An example of the cleaning at 205 is illustrated in FIG.3, with tubular conduit 62 being free, or at least substantially free,of solids, solid matter, particulate matter, and/or downhole equipmentand/or devices subsequent to the cleaning at 205.

As discussed herein with reference to FIG. 1, the downhole tubular mayinclude a plurality of existing perforations. Under these conditions,the adding new perforations at 210, which also may be referred to hereinas re-perforating the downhole tubular, may include forming, generating,and/or defining a plurality of spaced-apart new perforations within thedownhole tubular. The plurality of spaced-apart new perforations may beutilized to permit stimulation and/or fracturing of new and/or differentportions and/or region(s) of the subterranean formation, as discussed inmore detail herein. The adding at 210, when utilized, may be performedprior to the positioning at 215, prior to the positioning at 220, and/orprior to the stimulating at 225. An example of the adding at 210 isillustrated in FIG. 4, with downhole tubular 60 including both aplurality of existing perforations 70 and a plurality of newperforations 80.

The adding at 210 may be accomplished in any suitable manner. Asexamples, the adding at 210 may be performed utilizing any suitableautonomous and/or wireline-attached perforation gun and/or perforationdevice, such as a shape charge perforation device.

Positioning the plurality of isolation structures at 215 may includepositioning the plurality of isolation structures within the tubularconduit that is defined by the downhole tubular. The positioning at 215additionally or alternatively may include positioning the plurality ofisolation structures to form, define, and/or delineate a plurality ofspaced-apart stimulation zones within the tubular conduit. As discussed,the downhole tubular may include a plurality of spaced-apart existingperforations that provides fluid communication between the tubularconduit and the subterranean formation. Under these conditions, thepositioning at 215 may include positioning the plurality of isolationstructures such that each stimulation zone in the plurality ofspaced-apart stimulation zones includes a corresponding subset of theplurality of spaced-apart existing perforations.

Examples of the positioning at 215 are illustrated in FIGS. 5-7. FIG. 5illustrates the broad concept of positioning a plurality of isolationstructures 90 within a tubular conduit 62 to define a plurality ofspaced-apart stimulation zones 110 within the tubular conduit. In theillustrated example, the plurality of spaced-apart stimulation zonesincludes an initial stimulation zone 112, which includes an initialsubset 72 of the plurality of spaced-apart existing perforations 70, anadjacent stimulation zone 114, which includes an adjacent subset 74 ofthe plurality of spaced-apart existing perforations 70, and a subsequentstimulation zone 116, which includes a subsequent subset 76 of theplurality of spaced-apart existing perforations 70.

FIG. 6 illustrates that isolation structures 90 may include and/or befrangible isolation structures 92 that include frangible isolationdevices 100. Each frangible isolation structure 92 may resist fluidflow, within the tubular conduit, therepast, may resist fluid flow froman uphole region of the tubular conduit to a downhole region of thetubular conduit, and/or may resist fluid flow from the downhole regionof the tubular conduit to the uphole region of the tubular conduit.Thus, and as illustrated, stimulation zones 110 may be fluidly and/orhydraulically isolated from one another, at least within tubular conduit62, subsequent to the positioning at 215. When the positioning at 215includes positioning frangible isolation structures 92, the positioningat 215 may include positioning an initial frangible isolation device 102between initial stimulation zone 112 and adjacent stimulation zone 114and/or positioning an adjacent frangible isolation device 104 betweenadjacent stimulation zone 114 and subsequent stimulation zone 116.

FIG. 7 illustrates that isolation structures 90 may include and/or beisolation device seats 94 that are configured to receive the isolationdevice. Under these conditions, and as illustrated, stimulation zones110 may be in fluid and/or hydraulic communication with one anotheruntil a respective isolation device is positioned upon a correspondingisolation device seat 94. When the positioning at 215 includespositioning isolation device seats 94, the positioning at 215 mayinclude positioning an initial isolation device seat between initialstimulation zone 112 and adjacent stimulation zone 114 and/orpositioning a subsequent isolation device seat between adjacentstimulation zone 114 and subsequent stimulation zone 116.

The positioning at 215 may be accomplished in any suitable manner. As anexample, the positioning at 215 may include operatively engaging a givenisolation structure within a corresponding region of the downholetubular. As another example, the positioning at 215 may includepositioning such that the plurality of isolation structures isspaced-apart from one another along a length of the tubular conduit. Asyet another example, the positioning at 215 may include positioning suchthat each adjacent pair of isolation structures separates, bounds,and/or delineates a corresponding stimulation zone of the plurality ofspaced-apart stimulation zones within the tubular conduit. As anotherexample, the positioning at 215 may include flowing, within the tubularconduit and/or from a surface region, each isolation structure in theplurality of isolation structures to the corresponding region of thedownhole tubular. As additional examples, the positioning at 215 mayinclude autonomously positioning at least a subset of the plurality ofisolation structures, positioning at least a subset of the plurality ofisolation structures utilizing a wireline, positioning at least a subsetof the plurality of isolation structures utilizing jointed pipe,utilizing coiled tubing, and/or utilizing a tractor.

It is within the scope of the present disclosure that, subsequent to thepositioning at 215, the isolation structures may include any suitablespacing, relative spacing, and/or average spacing therebetween. Asexamples, a spacing, or an average spacing, between adjacent isolationstructures may be at least 5 meters, at least 8 meters, at least 10meters, at least 20 meters, at least 50 meters, at least 100 meters, atleast 200 meters, at least 300 meters, at least 400 meters, at least 500meters, at most 3000 meters, at most 2000 meters, at most 1000 meters,and/or at most 500 meters.

The positioning at 215 may include positioning the plurality ofisolation structures in any suitable order, in any suitable relativeorder, and/or with any suitable sequence. As an example, the positioningat 215 may include sequentially positioning the plurality of isolationstructures within the tubular conduit to define the plurality ofspaced-apart stimulation zones. The sequentially positioning may includesequentially positioning such that each isolation structure in theplurality of isolation structures is uphole from a, or from all,previously positioned isolation structures of the plurality of isolationstructures.

When the positioning at 215 includes positioning the plurality ofisolation structures in the form of the plurality of isolation deviceseats, methods 200 further may include the positioning, at 220, theinitial isolation device, which may be performed prior to thestimulating at 225. The positioning at 220 may include positioning theinitial isolation device on the initial isolation device seat. Whencombined with a corresponding isolation device, the isolation deviceseats may be configured to resist fluid flow from an uphole region ofthe tubular conduit, which is uphole from the isolation device seat, toand/or toward a downhole region of the tubular conduit, which isdownhole from the isolation device seat. Thus, the positioning at 220may include fluidly and/or hydraulically isolating the initialstimulation zone from the adjacent stimulation zone and/or from otherstimulation zones that are downhole from the initial stimulation zone.However, fluid communication still may be present among the otherstimulation zones that are downhole from the initial stimulation zone.This is illustrated in FIG. 10, with initial isolation device 102restricting fluid communication between initial stimulation zone 112 andadjacent stimulation zone 114.

The positioning at 220 may be accomplished in any suitable manner. As anexample, the positioning at 220 may include flowing the initialisolation device into contact with the initial isolation device seat. Asanother example, the positioning at 220 may include seating the initialisolation device on the initial isolation device seat. The initialisolation device may include and/or be any suitable structure, anexample of which includes an initial isolation ball.

Stimulating the initial region of the subterranean formation at 225 mayinclude stimulating a region of the subterranean formation that isassociated with the initial stimulation zone. Stated another way, theinitial region of the subterranean formation may surround the initialstimulation zone, may contain the initial stimulation zone, and/or maybe in fluid communication with the initial stimulation zone via theinitial subset of the plurality of spaced-apart existing perforations.

The stimulating at 225 may be accomplished in any suitable manner. As anexample, the stimulating at 225 may include injecting a stimulant fluidfrom a surface region, via the tubular conduit, through the initialsubset of the plurality of spaced-apart existing perforations, and intothe subterranean formation. This may include injecting through theinitial subset of the plurality of spaced-apart existing perforationswhile, at the same time, resisting, blocking, and/or occluding flow ofthe stimulant fluid past the initial isolation device and/or to, into,and/or through stimulation zones that are downhole from the initialstimulation zone.

As another example, the stimulating at 225 may include injecting afracturing fluid into the initial region of the subterranean formationto fracture the initial region of the subterranean formation. As yetanother example, the stimulating at 225 may include injecting aproppant, or a proppant slurry, into the initial region of thesubterranean formation to prop one or more fractures that may extendwithin the initial region of the subterranean formation. As anotherexample, the stimulating at 225 may include injecting an acid into theinitial region of the subterranean formation to dissolve at least aportion of the initial region of the subterranean formation. As yetanother example, the stimulating at 225 may include bullheading thestimulant fluid into the tubular conduit from the surface region. Thismay include flowing the stimulant fluid, in fluid contact with thedownhole tubular, between the surface region and the initial stimulationzone.

It is within the scope of the present disclosure that the stimulating at225 may include stimulating an entirety of the initial region of thesubterranean formation and/or flowing the stimulant fluid through eachof the initial subset of the plurality of existing perforations duringan entirety of a duration of the stimulating at 225. This is illustratedin FIGS. 8-10 by stimulated regions 38. Stimulated regions 38 are formedwithin initial region 32 of the subterranean formation via flow ofstimulant fluid 120 into the subterranean formation.

Alternatively, it also is within the scope of the present disclosurethat the stimulating at 225 may include stimulating in one or moresteps, or stages. As an example, the stimulating at 225 may includeinjecting the stimulant fluid into the subterranean formation via theinitial subset of the plurality of spaced-apart existing perforationsfor a first stimulation time period and subsequently sealing a mostfluid-receptive fraction of the initial subset of the plurality ofspaced-apart existing perforations. Subsequently, the stimulating at 225may include injecting the stimulant fluid into the subterraneanformation via a remainder of the initial subset of the plurality ofspaced-apart existing perforations for a second stimulation time period.

As another example, and when methods 200 include the adding at 210, theinitial stimulation zone may include a plurality of initial perforationsthat includes both the initial subset of the plurality of spaced-apartexisting perforations and an initial subset of the plurality ofspaced-apart new perforations. Under these conditions, the stimulatingat 225 may include injecting the stimulant fluid into the subterraneanformation via both the initial subset of the plurality of spaced-apartexisting perforations and the initial subset of the plurality ofspaced-apart new perforations for the first stimulation time period. Thestimulating at 225 then may include sealing a most fluid-receptivefraction of the plurality of initial perforations and subsequentlyinjecting the stimulant fluid into the subterranean formation via aremainder of the plurality of initial perforations for a secondstimulation time period.

This multi-step stimulation is illustrated in FIGS. 20-22, whichillustrate a downhole tubular 60, which defines a tubular conduit 62,extending within a subterranean formation 30. Downhole tubular 60 mayinclude a plurality of existing perforations 70 and/or a plurality ofnew perforations 80, which collectively may be referred to herein asperforations 138.

As illustrated in FIG. 20, a majority of stimulant fluid 120, which issupplied to subterranean formation 30 via tubular conduit 62, initiallymay flow into the subterranean formation via a most fluid-receptivefraction 140 of perforations 138. Subsequently, and as illustrated inFIG. 21, most fluid-receptive fraction 140 of perforations 138 may besealed, such as utilizing sealing devices 130. This sealing of mostfluid-receptive fraction 140 may focus, or direct, flow of stimulantfluid 120 into the subterranean formation via a remainder ofperforations 138 (e.g., an unsealed fraction of perforations 138), asillustrated in FIG. 21, thereby improving stimulation of region(s) ofsubterranean 30 that are not in direct fluid communication with mostfluid-receptive fraction 140. This multi-step stimulation process may berepeated any suitable number of times until regions of the subterraneanformation associated with all perforations 138 have been satisfactorilystimulated and/or until all perforations 138 have been sealed bycorresponding sealing devices 130, as illustrated in FIG. 22.

Sealing the initial subset of the plurality of perforations at 230 mayinclude sealing each perforation in the initial subset of the pluralityof spaced-apart existing perforations and/or sealing each perforation inthe plurality of spaced-apart new perforations with a correspondinginitial sealing device. This may include flowing a plurality of initialsealing devices, via the tubular conduit and/or within the stimulantfluid, into contact with corresponding perforations in the initialsubset of the plurality of perforations.

It is within the scope of the present disclosure that the sealing at 230may include concurrently, or at least substantially concurrently,sealing each and/or every perforation in the initial subset of theplurality of perforations. Alternatively, it also is within the scope ofthe present disclosure that the sealing at 230 may include sealing theplurality of perforations in a plurality of steps, or stages, asdiscussed herein with reference to the stimulating at 225.

The sealing at 230 is illustrated in FIGS. 8-10 and 20-22. Asillustrated therein, and subsequent to stimulation of the subterraneanformation with stimulant fluid 120 to form a plurality of stimulatedregions 38 therein, sealing devices 130 may be utilized to seal theplurality of spaced-apart existing perforations 70, thereby restrictingfluid flow from the tubular conduit and into the subterranean formationvia the plurality of existing perforations. This may permitpressurization of initial stimulation zone 112 with stimulant fluid 120.

Establishing fluid communication between the initial stimulation zoneand the adjacent stimulation zone at 235 may include establishing thefluid communication while maintaining the sealing at 230. Stated anotherway, the establishing at 235 may include establishing fluidcommunication between the initial stimulation zone and the adjacentstimulation zone while, at the same time, restricting fluid flow betweenthe tubular conduit and the subterranean formation via the initialsubset of the plurality of perforations. The adjacent stimulation zoneis downhole from the initial stimulation zone.

The establishing at 235 may include establishing the fluid communicationin any suitable manner. As an example, and as illustrated in thetransition from FIG. 8 to FIG. 11, the establishing at 235 may includeremoving initial isolation device 102 from isolation structure 90 thatseparates initial stimulation zone 112 from subsequent stimulation zone114 and/or removing the isolation structure that includes the initialisolation device.

As another example, and when the positioning at 215 includes positioningthe plurality of frangible isolation structures, the establishing at 235may include breaking, shattering, and/or otherwise removing an initialfrangible isolation structure that extends between, or fluidlyseparates, the initial stimulation zone and the adjacent stimulationzone. This is illustrated in the transition from FIG. 9 to FIG. 12, withinitial frangible isolation device 102 being present in FIG. 9 andabsent, or removed, from isolation structure 90 in FIG. 12.

When the isolation structure includes the frangible isolation structure,the establishing at 235 may include one or more of generating ashockwave within a wellbore fluid that extends within the tubularconduit to provide a motive force for shattering of the frangibleisolation structure and/or pressurizing the wellbore fluid to greaterthan a threshold shattering pressure for the frangible isolationstructure. Additionally or alternatively, the frangible isolationstructure may be configured to shatter responsive to receipt of anothersuitable transition signal, and the establishing at 235 may includeproviding the transition signal to the frangible isolation structure.Additional examples of transition signals include a wired transitionsignal, a wireless transition signal, an electromagnetic transitionsignal, an acoustic transition signal, a pressure pulse of greater thana predetermined magnitude, a predetermined pressure pulse sequence, apredetermined acoustic signal, and/or a predetermined wireless signal.

As yet another example, and when methods 200 include the positioning at220, the establishing at 235 may include shearing the initial isolationdevice seat and/or forcing the initial isolation device through theinitial isolation device seat. This is illustrated in the transitionfrom FIG. 10 to FIG. 13, with initial isolation ball 102 being presenton isolation device seat 94 and thereby fluidly isolating initialstimulation zone 112 from adjacent stimulation zone 114 in FIG. 10 andthe initial isolation ball being absent from the corresponding isolationdevice seat in FIG. 13. The shearing and/or forcing may be accomplishedin any suitable manner. As an example, the shearing and/or forcing mayinclude pressurizing the tubular conduit to greater than a thresholdshearing and/or forcing pressure.

When methods 200 include the positioning at 220, methods 200 also, orsubsequently, may include the positioning at 240. The positioning at 240may be performed subsequent to the establishing at 235 and/or prior tothe stimulating at 245.

The positioning at 240, when performed, may include positioning theadjacent isolation device on an adjacent isolation device seat tohydraulically isolate the adjacent stimulation zone from stimulationzones that are downhole from the adjacent stimulation zone. Thepositioning at 240 may be similar, or at least substantially similar, tothe positioning at 220, which is discussed in more detail herein.

It is within the scope of the present disclosure that the adjacentisolation device may be different from the initial isolation deviceand/or may be distinct from the initial stimulation device. Under theseconditions, the isolation device seats may progressively differ, orincrease, in size from a most uphole isolation device seat to a mostdownhole isolation device seat; and the positioning at 240 may includeflowing the adjacent isolation device, such as from the surface region,into contact with the adjacent isolation device seat.

Alternatively, it also is within the scope of the present disclosurethat the adjacent isolation device includes, or is, the initialisolation device. Under these conditions, each isolation device seat maybe the same, or at least substantially the same, size as each otherisolation device seat; and the positioning at 240 may include flowingthe initial isolation device from the initial stimulation device seat toand/or into contact with the adjacent isolation device seat.

The positioning at 240 is illustrated in FIG. 13. As illustratedtherein, adjacent isolation device 104, in the form of an adjacentisolation ball 104, is positioned upon isolation device seat 94 thatextends between adjacent stimulation zone 114 and subsequent stimulationzone 116.

Stimulating the adjacent region of the subterranean formation at 245 mayinclude stimulating any suitable adjacent region of the subterraneanformation that is associated with the adjacent stimulation zone. Thestimulating at 245 may be similar, or at least substantially similar, tothe stimulating at 225. The adjacent stimulation zone may include anadjacent subset of the plurality of perforations, and the stimulating at245 may include injecting the stimulant fluid from the surface region,via the tubular conduit, through the initial stimulation zone, throughthe adjacent subset of the plurality of spaced-apart perforations, andinto the subterranean formation. The stimulating at 245 further mayinclude resisting flow of the stimulant fluid through stimulation zonesof the plurality of stimulation zones that are downhole from theadjacent stimulation zone. Methods 200 also may include resisting flowof the stimulant fluid through the initial subset of the plurality ofperforations during the stimulating at 245. As such, methods 200 focusflow of the stimulant fluid through the adjacent subset of the pluralityof perforations, thereby providing improved, focused, and/or directedstimulation of the adjacent region of the subterranean formation.

The stimulating at 245 is illustrated by the transition from FIGS. 11-13to FIGS. 14-17. As illustrated in FIGS. 11-13, and prior to thestimulating at 245, stimulated regions 38 extend within initial region32 but not within adjacent region 34 of the subterranean formation.However, and subsequent to the stimulating at 245, stimulated regions 38extend in both initial region 32 and adjacent region 34.

It is within the scope of the present disclosure that methods 200 mayinclude stimulating, or sequentially stimulating, any suitable number ofdifferent, distinct, and/or spaced-apart regions of the subterraneanformation. This generally will include progressing in a downholedirection, with each stimulated region being downhole from previouslystimulated regions of the subterranean formation.

As an example, and subsequent to the stimulating at 245, methods 200further may include sealing the adjacent subset of the plurality ofperforations at 250. The sealing at 250 may be similar, or at leastsubstantially similar, to the sealing at 230, which is discussed herein.

Subsequently, methods 200 may include establishing fluid communicationbetween the adjacent stimulation zone and the subsequent stimulationzone at 255. As discussed, the subsequent stimulation zone may bedownhole from the adjacent stimulation zone, and the establishing at 255may include establishing the fluid communication while maintaining thesealing at 230 and also while maintaining the sealing at 250. Theestablishing at 255 may be similar, or at least substantially similar,to the establishing at 235.

Subsequently, methods 200 may include stimulating a subsequent region ofthe subterranean formation at 260, which is associated with thesubsequent stimulation zone. This may include flowing the stimulantfluid from the surface region, via the tubular conduit, through theinitial stimulation zone, through the adjacent stimulation zone, andthrough a subsequent subset of the plurality of perforations, which isassociated with the subsequent stimulation zone. The stimulating at 260further may include flowing the stimulant fluid into the subterraneanformation via the subsequent subset of the plurality of perforationswhile resisting flow of the stimulant fluid through stimulation zonesthat are downhole from the subsequent stimulation zone.

This is illustrated in FIGS. 17-18, with initial stimulation zone 112,adjacent stimulation zone 114, and subsequent stimulation zone 116 allincluding stimulated regions 38 extending therein. Initial stimulationzone 112 includes an initial subset 72 of the plurality of spaced-apartexisting perforations 70, which is sealed by initial sealing devices132. Adjacent stimulation zone 114 includes an adjacent subset 74 of theplurality of spaced-apart existing perforations 70, which is sealed byadjacent sealing devices 134, and subsequent stimulation zone 116includes a subsequent subset 76 of the plurality of spaced-apartexisting perforations 70, which is sealed by subsequent sealing devices136.

Subsequent to stimulation of a desired number of regions of thesubterranean formation via corresponding stimulation zones, methods 200further may include clearing the tubular conduit at 265. This mayinclude clearing, or cleaning, the tubular conduit to permit and/orfacilitate subsequent production from the subterranean formation via thetubular conduit.

The clearing at 265 may include clearing in any suitable manner. Asexamples, the clearing at 265 may include removing at least a subset ofthe plurality of isolation structures from the tubular conduit, removingat least a subset of the plurality of isolation devices from the tubularconduit, and/or removing at least a subset of the plurality of sealingdevices from the tubular conduit.

As additional examples, the clearing at 265 may include running a millthrough the tubular conduit, such as to mill away the plurality ofisolation structures, the plurality of isolation devices, and/or theplurality of sealing devices, and/or providing an acid to the tubularconduit, such as to corrode and/or dissolve the plurality of isolationstructures, the plurality of isolation devices, and/or the plurality ofsealing devices. This is illustrated in FIG. 19, with tubular conduit 62being free of isolation structures, isolation devices, and/or sealingdevices.

In the present disclosure, several structures, subsets, and/or regionsare described with the adjectives “initial,” “adjacent,” and“subsequent.” In general, “initial” structures, subsets, and/or regionswill be utilized, during methods 200, prior to “adjacent” structures,subsets, and/or regions, which will be utilized, during methods 200,prior to “subsequent” structures, subsets, and/or regions. Thus, andwhile indicative of timing, sequencing, and/or chronology, theadjectives “initial,” “adjacent,” and “subsequent” are not intended toconvey, or to require, a specific spatial relationship, immediateadjacency, and/or an abutting arrangement among the various structures,subsets, and/or regions. With this in mind, the adjectives “initial,”“adjacent,” and “subsequent” may be replaced with the adjectives“first,” “second,” and “third” or “uphole,” “middle,” and “downhole,”respectively, without departing from the scope of the presentdisclosure.

In the present disclosure, several of the illustrative, non-exclusiveexamples have been discussed and/or presented in the context of flowdiagrams, or flow charts, in which the methods are shown and describedas a series of blocks, or steps. Unless specifically set forth in theaccompanying description, it is within the scope of the presentdisclosure that the order of the blocks may vary from the illustratedorder in the flow diagram, including with two or more of the blocks (orsteps) occurring in a different order and/or concurrently.

As used herein, the term “and/or” placed between a first entity and asecond entity means one of (1) the first entity, (2) the second entity,and (3) the first entity and the second entity. Multiple entities listedwith “and/or” should be construed in the same manner, i.e., “one ormore” of the entities so conjoined. Other entities may optionally bepresent other than the entities specifically identified by the “and/or”clause, whether related or unrelated to those entities specificallyidentified. Thus, as a non-limiting example, a reference to “A and/orB,” when used in conjunction with open-ended language such as“comprising” may refer, in one embodiment, to A only (optionallyincluding entities other than B); in another embodiment, to B only(optionally including entities other than A); in yet another embodiment,to both A and B (optionally including other entities). These entitiesmay refer to elements, actions, structures, steps, operations, values,and the like.

As used herein, the phrase “at least one,” in reference to a list of oneor more entities should be understood to mean at least one entityselected from any one or more of the entity in the list of entities, butnot necessarily including at least one of each and every entityspecifically listed within the list of entities and not excluding anycombinations of entities in the list of entities. This definition alsoallows that entities may optionally be present other than the entitiesspecifically identified within the list of entities to which the phrase“at least one” refers, whether related or unrelated to those entitiesspecifically identified. Thus, as a non-limiting example, “at least oneof A and B” (or, equivalently, “at least one of A or B,” or,equivalently “at least one of A and/or B”) may refer, in one embodiment,to at least one, optionally including more than one, A, with no Bpresent (and optionally including entities other than B); in anotherembodiment, to at least one, optionally including more than one, B, withno A present (and optionally including entities other than A); in yetanother embodiment, to at least one, optionally including more than one,A, and at least one, optionally including more than one, B (andoptionally including other entities). In other words, the phrases “atleast one,” “one or more,” and “and/or” are open-ended expressions thatare both conjunctive and disjunctive in operation. For example, each ofthe expressions “at least one of A, B and C,” “at least one of A, B, orC,” “one or more of A, B, and C,” “one or more of A, B, or C” and “A, B,and/or C” may mean A alone, B alone, C alone, A and B together, A and Ctogether, B and C together, A, B and C together, and optionally any ofthe above in combination with at least one other entity.

In the event that any patents, patent applications, or other referencesare incorporated by reference herein and (1) define a term in a mannerthat is inconsistent with and/or (2) are otherwise inconsistent with,either the non-incorporated portion of the present disclosure or any ofthe other incorporated references, the non-incorporated portion of thepresent disclosure shall control, and the term or incorporateddisclosure therein shall only control with respect to the reference inwhich the term is defined and/or the incorporated disclosure was presentoriginally.

As used herein the terms “adapted” and “configured” mean that theelement, component, or other subject matter is designed and/or intendedto perform a given function. Thus, the use of the terms “adapted” and“configured” should not be construed to mean that a given element,component, or other subject matter is simply “capable of” performing agiven function but that the element, component, and/or other subjectmatter is specifically selected, created, implemented, utilized,programmed, and/or designed for the purpose of performing the function.It also is within the scope of the present disclosure that elements,components, and/or other recited subject matter that is recited as beingadapted to perform a particular function may additionally oralternatively be described as being configured to perform that function,and vice versa.

As used herein, the phrase, “for example,” the phrase, “as an example,”and/or simply the term “example,” when used with reference to one ormore components, features, details, structures, embodiments, and/ormethods according to the present disclosure, are intended to convey thatthe described component, feature, detail, structure, embodiment, and/ormethod is an illustrative, non-exclusive example of components,features, details, structures, embodiments, and/or methods according tothe present disclosure. Thus, the described component, feature, detail,structure, embodiment, and/or method is not intended to be limiting,required, or exclusive/exhaustive; and other components, features,details, structures, embodiments, and/or methods, including structurallyand/or functionally similar and/or equivalent components, features,details, structures, embodiments, and/or methods, are also within thescope of the present disclosure.

INDUSTRIAL APPLICABILITY

The systems, wells, and methods disclosed herein are applicable to theoil and gas, well drilling, well completion, and/or well re-completionindustries.

It is believed that the disclosure set forth above encompasses multipledistinct inventions with independent utility. While each of theseinventions has been disclosed in its preferred form, the specificembodiments thereof as disclosed and illustrated herein are not to beconsidered in a limiting sense as numerous variations are possible. Thesubject matter of the inventions includes all novel and non-obviouscombinations and subcombinations of the various elements, features,functions and/or properties disclosed herein. Similarly, where theclaims recite “a” or “a first” element or the equivalent thereof, suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.

It is believed that the following claims particularly point out certaincombinations and subcombinations that are directed to one of thedisclosed inventions and are novel and non-obvious. Inventions embodiedin other combinations and subcombinations of features, functions,elements and/or properties may be claimed through amendment of thepresent claims or presentation of new claims in this or a relatedapplication. Such amended or new claims, whether they are directed to adifferent invention or directed to the same invention, whetherdifferent, broader, narrower, or equal in scope to the original claims,are also regarded as included within the subject matter of theinventions of the present disclosure.

What we claim:
 1. A method for refracturing a subterranean formation viaa hydrocarbon well including a downhole tubular extending within awellbore formed within the subterranean formation, the methodcomprising: positioning a plurality of isolation structures within atubular conduit defined by the downhole tubular to define a plurality ofspaced-apart stimulation zones within the tubular conduit, wherein thedownhole tubular includes a plurality of spaced-apart existingperforations that provides fluid communication between the tubularconduit and the subterranean formation, and further wherein eachstimulation zone of the plurality of spaced-apart stimulation zonesincludes a corresponding subset of the plurality of spaced-apartexisting perforations; subsequent to the positioning, stimulating aninitial region of the subterranean formation associated with an initialstimulation zone of the plurality of spaced-apart stimulation zones,wherein the initial stimulation zone includes an initial subset of theplurality of spaced-apart existing perforations, wherein the stimulatingthe initial region includes injecting a stimulant fluid from a surfaceregion, via the tubular conduit, through the initial subset of theplurality of spaced-apart existing perforations, and into thesubterranean formation while resisting flow of the stimulant fluidthrough stimulation zones of the plurality of spaced-apart stimulationzones that are downhole from the initial stimulation zone; sealing theinitial subset of the plurality of spaced-apart existing perforations;establishing fluid communication between the initial stimulation zoneand an adjacent stimulation zone of the plurality of spaced-apartstimulation zones within the tubular conduit while maintaining thesealing the initial subset of the plurality of spaced-apart existingperforations, wherein the adjacent stimulation zone is downhole from theinitial stimulation zone; and stimulating an adjacent region of thesubterranean formation associated with the adjacent stimulation zone,wherein the adjacent stimulation zone includes an adjacent subset of theplurality of spaced-apart existing perforations, wherein the stimulatingthe adjacent region includes injecting the stimulant fluid from thesurface region, via the tubular conduit, through the initial stimulationzone, through the adjacent subset of the plurality of spaced-apartexisting perforations, and into the subterranean formation whileresisting flow of the stimulant fluid through stimulation zones of theplurality of spaced-apart stimulation zones that are downhole from theadjacent stimulation zone.
 2. The method of claim 1, wherein thepositioning includes sequentially positioning the plurality of isolationstructures within the tubular conduit to define the plurality ofspaced-apart stimulation zones, wherein the sequentially positioningincludes positioning such that each isolation structure of the pluralityof isolation structures is uphole from previously positioned isolationstructures of the plurality of isolation structures.
 3. The method ofclaim 1, wherein the positioning includes positioning a plurality offrangible isolation structures, wherein each frangible isolationstructure of the plurality of frangible isolation structures resistsfluid flow from an uphole region of the tubular conduit, which is upholetherefrom, to a downhole region of the tubular conduit, which isdownhole therefrom.
 4. The method of claim 3, wherein the positioningincludes positioning an initial frangible isolation structure of theplurality of frangible isolation structures, which hydraulicallyisolates the initial stimulation zone from the adjacent stimulationzone, and further wherein the establishing includes shattering theinitial frangible isolation structure.
 5. The method of claim 4, whereinthe shattering includes at least one of: (i) generating a shockwavewithin a wellbore fluid, which extends within the tubular conduit, toprovide a motive force for the shattering; (ii) providing a transitionsignal to the initial frangible isolation structure, wherein the initialfrangible isolation structure is configured to shatter responsive toreceipt of the transition signal; and (iii) pressurizing the wellborefluid to greater than a threshold shattering pressure.
 6. The method ofclaim 5, wherein the transition signal includes at least one of: (i) apressure pulse of a predetermined magnitude; (ii) a predeterminedpressure pulse sequence; (iii) a predetermined acoustic signal; and (iv)a predetermined wireless signal.
 7. The method of claim 1, wherein thepositioning includes positioning a plurality of isolation device seatswithin the tubular conduit, wherein each isolation device seat, whencombined with a corresponding isolation device, resists fluid flow froman uphole region of the tubular conduit, which is uphole therefrom, to adownhole region of the tubular conduit, which is downhole therefrom. 8.The method of claim 7, wherein, subsequent to the positioning and priorto the stimulating the initial region, the method further includespositioning an initial isolation device on an initial isolation deviceseat to hydraulically isolate the initial stimulation zone from thestimulation zones of the plurality of spaced-apart stimulation zonesthat are downhole from the initial stimulation zone.
 9. The method ofclaim 8, wherein the positioning includes flowing the initial isolationdevice into contact with the initial isolation device seat.
 10. Themethod of claim 8, wherein the tubular conduit provides fluidcommunication among the stimulation zones of the plurality ofspaced-apart stimulation zones that are downhole from the initialstimulation zone.
 11. The method of claim 8, wherein the establishingincludes at least one of: (i) shearing the initial isolation deviceseat; and (ii) forcing the initial isolation device through the initialisolation device seat.
 12. The method of claim 8, wherein, subsequent tothe establishing and prior to the stimulating the adjacent region of thesubterranean formation, the method further includes positioning anadjacent isolation device on an adjacent isolation device seat tohydraulically isolate the adjacent stimulation zone from stimulationzones of the plurality of spaced-apart stimulation zones that aredownhole from the adjacent stimulation zone.
 13. The method of claim 1,wherein the stimulating the initial region of the subterranean formationincludes at least one of: (i) injecting a fracturing fluid into theinitial region of the subterranean formation to fracture the initialregion of the subterranean formation; (ii) injecting a proppant into theinitial region of the subterranean formation to prop one or morefractures that extend within the initial region of the subterraneanformation; (iii) injecting an acid into the initial region of thesubterranean formation to dissolve at least a portion of the initialregion of the subterranean formation; and (iv) bullheading the stimulantfluid into the tubular conduit from the surface region.
 14. The methodof claim 1, wherein the stimulating the adjacent region of thesubterranean formation includes at least one of: (i) injecting afracturing fluid into the adjacent region of the subterranean formationto fracture the adjacent region of the subterranean formation; (ii)injecting a proppant into the adjacent region of the subterraneanformation to prop one or more fractures that extend within the adjacentregion of the subterranean formation; (iii) injecting an acid into theadjacent region of the subterranean formation to dissolve at least aportion of the adjacent region of the subterranean formation; and (iv)bullheading the stimulant fluid into the tubular conduit from thesurface region.
 15. The method of claim 1, wherein the sealing theinitial subset of the plurality of spaced-apart existing perforationsincludes sealing with a plurality of initial sealing devices.
 16. Themethod of claim 1, wherein, subsequent to the stimulating the adjacentregion of the subterranean formation, the method further includes:sealing the adjacent subset of the plurality of spaced-apart existingperforations; establishing fluid communication between the adjacentstimulation zone and a subsequent stimulation zone of the plurality ofspaced-apart stimulation zones, which is downhole from the adjacentstimulation zone, while maintaining the sealing the initial subset ofthe plurality of spaced-apart existing perforations and also maintainingthe sealing the adjacent subset of the plurality of spaced-apartexisting perforations; and stimulating a subsequent region of thesubterranean formation associated with the subsequent stimulation zone,wherein the stimulating the subsequent region includes flowing thestimulant fluid from the surface region, via the tubular conduit,through the initial stimulation zone, through the adjacent stimulationzone, through a subsequent subset of the plurality of spaced-apartexisting perforations, which is associated with the subsequentstimulation zone, and into the subterranean formation while resistingflow of the stimulant fluid through stimulation zones of the pluralityof spaced-apart stimulation zones that are downhole from the subsequentstimulation zone.
 17. The method of claim 1, wherein the method includessequentially stimulating a region of the subterranean formationassociated with each stimulation zone of the plurality of spaced-apartstimulation zones, wherein each subsequently stimulated region of thesubterranean formation is downhole from a previously stimulatedstimulation zone.
 18. The method of claim 1, wherein, prior to thestimulating the initial region of the subterranean formation, the methodfurther includes adding new perforations to the downhole tubular,wherein the adding new perforations to the downhole tubular includesgenerating a plurality of spaced-apart new perforations within thedownhole tubular.
 19. The method of claim 17, wherein the initialstimulation zone includes a plurality of initial perforations, whichincludes both the initial subset of the plurality of spaced-apartexisting perforations and an initial subset of the plurality ofspaced-apart new perforations, and further wherein the stimulating theinitial region of the subterranean formation further includes: (i)injecting the stimulant fluid into the subterranean formation via boththe initial subset of the plurality of spaced-apart existingperforations and the initial subset of the plurality of spaced-apart newperforations for a first stimulation time period; (ii) sealing a mostfluid-receptive fraction of the plurality of initial perforations; and(iii) injecting the stimulant fluid into the subterranean formation viaa remainder of the plurality of initial perforations for a secondstimulation time period.
 20. The method of claim 1, wherein thestimulating the initial region of the subterranean formation includes:(i) injecting the stimulant fluid into the subterranean formation viathe initial subset of the plurality of spaced-apart existingperforations for a first stimulation time period; (ii) sealing a mostfluid-receptive fraction of the initial subset of the plurality ofspaced-apart existing perforations; and (iii) injecting the stimulantfluid into the subterranean formation via a remainder of the initialsubset of the plurality of spaced-apart existing perforations for asecond stimulation time period.
 21. The method of claim 1, wherein thesealing comprises using at least one of: (i) a plurality of ballsealers; (ii) a plurality of conformable sealers; (iii) a plurality ofbeads; (iv) a plurality of poly lactic acid beads; (v) a plurality offibers; (vi) a plurality of poly lactic acid fibers; (vii) a pluralityof rods; (viii) a plurality of poly lactic acid rods; and (ix)combinations thereof.
 22. The method of claim 1, wherein, prior to thepositioning the initial stimulation device, the method further includescleanout of the tubular conduit.
 23. The method of claim 22, wherein thecleanout includes flushing solids from the tubular conduit.
 24. Themethod of claim 22, wherein the cleanout includes utilizing coiledtubing.
 25. The method of claim 1, wherein, subsequent to stimulation ofa desired number of regions of the subterranean formation viacorresponding stimulation zones of the plurality of spaced-apartstimulation zones, the method further includes cleanout the tubularconduit.
 26. The method of claim 25, wherein the cleanout includes atleast one of: (i) removing the plurality of isolation structures fromthe tubular conduit; (ii) removing a plurality of isolation devices fromthe tubular conduit; and (iii) removing a plurality of sealing devicesfrom the tubular conduit.
 27. The method of claim 25, wherein thecleanout includes at least one of: (i) running a mill through thetubular conduit; and (ii) providing an acid to the tubular conduit.